Effect of different loading conditions on running mechanics at different velocities     

Germán Carretero-Navarro  Doménico Cherubini  Wolfgang Taube 《European Journal of Sport Science》2019,19(5):595-602

Weighted vests are widely used to improve running economy and performance. However, it is not well-studied how running mechanics are adapted to counteract the higher peak vertical ground reaction forces (Fpeak) while running with such a device. Therefore, the present study aimed to investigate the effects of different loading conditions on running mechanics at different velocities. Thirteen subjects participated in two separate sessions one week apart. In the first session, maximal aerobic speed (MAS) was determined through a maximal incremental running test while in the second session, they were instructed to run during one minute under different loading (0%, +10% and +20% of body mass [BM]) and velocity (60%, 80% and 100% of MAS) conditions in a random order. Spatiotemporal data were recorded and then running mechanics modelled using the spring-mass model. The main results indicated that vertical and leg stiffness (Kvert and Kleg, respectively) were increased (P?P?>?.05) when load was changed. At the same time, alterations of the running kinematics were observed such as longer contact times, reduced flight times, stride frequencies and step lengths, as well as an increase of the centre of mass dynamics. Based on these results it is assumed that runners maintain a certain stiffness level for each velocity despite different loading conditions. As a consequence, Fpeak increases and this probably causes spatiotemporal adjustments in the movement kinematics.  相似文献   

Performative technologies and teacher subjectivities: A conceptual framework     

Hans Englund  Jonas Gerdin 《British Educational Research Journal》2019,45(3):502-517

Critical educational literature suggests that an increased reliance upon performative technologies is currently transforming the very foundations from which teacher subjectivities are constructed. Arguably though, the number of studies pointing to this risk or tendency is considerably larger than the ones theorising why this should be the case. Further, in those cases where the relationship between performative technologies and teacher subjectivities is theorised, the psychological mechanisms that the technologies appeal to are seldom brought to the fore. Based on this, the purpose of this article is to theorise the psychological mechanisms that performative technologies appeal to and work through, by means of identifying, systematising and elaborating extant understandings of such mechanisms in the critical educational literature. The results are presented in the form of a conceptual framework (referred to as the CMIS-framework) which suggests that one and the same performative technology may play many different roles, where each such role appeals to and works through a particular psychological mechanism. Importantly, depending on the type of psychological mechanism that is appealed to, the CMIS-framework suggests that this will lead to teachers (un)consciously conducting particular forms of subjectivising work upon themselves, here referred to as compliance, mirroring, identification and self-realisation (CMIS).  相似文献   

REAL: Ein ressourcenadaptierendes mobiles Navigationssystem     

Wolfgang Wahlster  J?rg Baus  Christian Kray und Antonio Krüger 《Informatik - Forschung und Entwicklung》2001,16(4):233-241

Zusammenfassung.   Die intelligente Ressourcenadaption ist eine der gro?en Herausforderungen für die n?chste Generation mobiler Navigationssysteme. Da man typischerweise mehrere Fortbewegungsarten oder Verkehrsmittel kombinieren muss, um an einen Zielort zu gelangen, muss sichergestellt werden, dass mobile, allgegenw?rtige Navigationshilfen dies über eine jeweils situationsangepasste Benutzerschnittstelle unterstützen. Der notwendige Wechsel zwischen verschiedenen Positionierungstechnologien soll für den Endbenutzer m?glichst unbemerkt bleiben. Im folgenden wird ein hybrides Personennavigationssystem vorgestellt, das die in bestimmten Fortbewegungssituationen verfügbaren Positionierungstechnologien und deren Genauigkeit optimal nutzt, um die Pr?sentation der Wegbeschreibung auf verschiedene Endger?te und Ausgabemodalit?ten sowie die kognitive Ressourcenlage des Benutzers zu adaptieren. Eingegangen am 28. Februar 2001 / Angenommen am 8. August 2001  相似文献   

Targets and Tools in Dutch Access Policies     

Frans Kaiser  Hans Vossensteyn 《Higher Education Quarterly》2005,59(3):187-204

In 2004 the Dutch Ministry of Education, Culture and Science set a concrete target: by 2010, close to 50% of the age cohort should participate in higher education, following the targets set in the UK and Sweden. However clear the target is set, the ways to achieve it are far less specified. In the article a number of possible instruments to achieve the target are discussed and their relevance in the Dutch context is analysed. It is concluded that there are a limited number of policy instruments available. However, given the devolution of access policy to the higher education institutions and the influence of broader societal trends on participation our expectations on what government can do to reach its target need to be modest.  相似文献   

Emergent rationality in technological policy: Nuclear energy in the Federal Republic of Germany     

Wolfgang Fach  Edgar Grande 《Minerva》1992,30(1):14-27

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Editorial     

Donsbach  Wolfgang; Noelle-Neumann  Elisabeth; Traugott  Michael W.; Worcester  Robert 《Int. Journal of Public Opinion Research》2006,18(3):273-274

This issue of the Journal contains three interesting articlesabout central aspects of public opinion research, as well asan equal number of research notes that reflect the range oftopics that interest all public opinion researchers. Toshio Takeshita takes a turn at reconceptualizing agenda-settingstudies, using a taxonomy  相似文献   

International rights management and the Frankfurt book fair     

Hans Kim  Marisa Moura  Lynette Owen 《Publishing Research Quarterly》2004,20(2):44-54

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Changing Minds or Changing Channels?: Partisan News in an Age of Choice Kevin Arceneaux and Martin Johnson. Chicago,IL: University of Chicago Press, 2013.          下载免费PDF全文

Hans C. Schmidt 《Journal of American culture (Malden, Mass. : 2003)》2015,38(3):282-283

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The internationalization of European sports teams and the issue of national citizenship     

Hans Henrik Appel 《Sport in History》2016,36(4):538-540

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Effects of writing instruction and assessment on functional composition performance     

Hans Kuhlemeier  Huub Van Den Bergh 《Assessing Writing》1997,4(2):203-223

In this study the relationships between writing instruction and functional composition performance were analyzed. The data were obtained in a national assessment on the language proficiency of students in the third year of Dutch secondary education (age ±15). Multivariate multilevel analysis showed that 10 out of 36 instructional characteristics were related to functional composition performance. The effective instructional characteristics included: instruction and exercises in writing functional texts, writing for a specific purpose, tailoring to a particular audience, global rating of writing products by the teacher, and frequent evaluation of Dutch language proficiency through teacher-made tests and written assignments. No effects were found for the rather popular subskill exercises on idiom, syntax, spelling and punctuation, and for pre-writing activities, text revisions and peer-review. Furthermore, the effect of instructional characteristics was often different on one task than on another. Finally, there was little differential effectiveness for different groups of students. If one instructional characteristic was more effective than the other, this was generally true, to an equal degree, for boys and girls and for promoted and non-promoted students.  相似文献